This study investigates whether treatments for major depression validated with psychiatric patients are equally effective with primary medical care patients experiencing this disorder. The question of whether treatments can be transferred across service delivery settings arises since ambulatory medical patients experience depressions of possibly differing etiology, severity, symptomatology, and duration. This issue has major clinical and policy significance in light of repeated assertions that primary care physicians improperly treat their depressed patients, and initiatives by the NIMH D/ART Program and others which teach generalist physicians treatment standards refined with psychiatric patients. This study compares the clinical course of major depression in ambulatory medical patients provided "usual care" by their primary care physicians with the clinical course of similar patients treated with standardized pharmacotherapy (nortriptyline) alone or time-limited psychotherapy (interpersonal psychotherapy) alone. Patients at three Pittsburgh, PA primary health care centers will be screened with the Center For Epidemiologic Studies-Depression Scale, the Diagnostic Interview Schedule, and the Hamilton Rating Scale-Depression. Patients meeting diagnostic and severity criteria for a current major depression will be assessed by a psychiatrist to confirm the affective disorder, and they will be given laboratory tests to rule out medical contraindications to psychiatric treatment. 270 patients meeting all inclusionary and exclusionary criteria will be recruited for randomization to usual care, pharmacotherapy, or psychotherapy. Study patients will be followed for 18 months after treatment assignment. It is hypothesized that significantly more patients treated with pharmacotherapy or psychotherapy than patients receiving usual care will no longer meet DIS criteria for a major depression and have HRS-D scores -< 6 four months after starting treatment. Outcome on the diagnosis-severity criterion and other psychiatric, medical, and social indices also will be assessed at three prior and three subsequent time points so as to compare each treatment cohort's course of illness and time to wellness. The study will generate findings about the validity of transferring depression treatment standards across service delivery settings, and break new methodological ground by applying features of clinical trials methodology to the concerns of services research.